CN101071252A

CN101071252A - Focus adjustment method, focus adjustment apparatus, and control method thereof

Info

Publication number: CN101071252A
Application number: CNA200710102052XA
Authority: CN
Inventors: 平井信也; 寺山公太
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2006-05-10
Filing date: 2007-05-10
Publication date: 2007-11-14
Anticipated expiration: 2027-05-10
Also published as: CN101547314B; JP2007304280A; US7945152B2; CN101980524A; JP4262272B2; US8145049B2; EP1855466A2; KR20070109843A; CN100570471C; JP4182117B2; EP1855466A3; KR100815513B1; US20100226636A1; CN101547314A; JP2008070640A; US20070263997A1; CN101980524B; EP1855466B1

Abstract

The invention provideds a Focus adjustment method, a focus adjustment apparatus, and a control method thereof. The apparatus comprises a face position detection section (120) for detecting at least a position at which is present a person's face inside a frame using an image signal obtained from an image sensor (103) for photoelectrically converting an object image captured by a photographing optical system (101), a focus control section (114) for controlling the photographing optical system by referencing in-focus positions of the object image obtained inside focus detection areas for detecting focus states of the object image positioned in the frame, and a control section (112) for controlling the focus control section so as to reference at least one or the other of an in-focus position obtained in a first focus detection area in which is present a person's face and an in-focus position obtained in a second focus detection area in which is expected to be present a body of a person determining from the position of the face of the person.

Description

Focus adjusting method, focus adjusting apparatus and control method thereof

Technical field

Present invention relates in general to a kind of focus adjusting method, focus adjusting apparatus and control method thereof, relate in particular to and a kind ofly use facial detection information to carry out the technology of automatic focusing.

Background technology

Traditionally, when utilization is fixed on the autofocus camera shooting subject image of picture central authorities with the focus detection zone, the subject image must be placed on central authorities, carry out Focus hold, take composition then.

Therefore, developed following method: a plurality of focus detection zone is set, its objective is not change the shooting composition, promptly do not use Focus hold, also can carry out automatic focusing in picture.This technology has two kinds of methods, and a kind of method is the user selects an expectation from a plurality of surveyed areas focus detection zone, and another kind of method is the focal length that the focus detection result according to a plurality of focus detection zone estimates main subject and determines to use.In the two method, a kind of method in back is more convenient, does not worry selecting the focus detection zone because the user can take.Yet this method exists focus detection zone of selecting automatically not necessarily to detect the problem that the user wishes the focus of the subject of taking.

A method that addresses this problem is a kind of picture pick-up device, this picture pick-up device is in order to constitute people's face in the inspection image data by qualification for the precision that the people improves above-mentioned estimation, the focus detection zone is set comprising detected face, and correspondingly regulates focus (referring to TOHKEMY 2003-107335 communique).TOHKEMY 2003-107335 communique has been described a kind of picture pick-up device, this picture pick-up device constitutes the face of subject in the inspection image data for the precision that improves above-mentioned estimation by the face that is defined as subject, the focus detection zone is set comprising detected face, and correspondingly regulates focus.In TOHKEMY 2003-107335 communique, use the action of focusing of detected face, thereby reduced the wrong possibility that focuses on other subject.

Yet, utilize TOHKEMY 2003-107335 communique, low and can not obtain under the sufficient focus detection data conditions in facial contrast, even can detect face, can not regulate focus sometimes.Equally, if the subjects such as vase at different distance place are than the more close picture pick-up device of face in the focus detection zone,, can not regulate focus even then can detect face.

Summary of the invention

Therefore, consider that the problems referred to above have made the present invention, and the objective of the invention is to make and to focus on the subject of user's expection in the impossible breakthrough mode of conventional art.

In order to address these problems and realize this purpose, according to a first aspect of the invention, a kind of focus adjusting apparatus comprises: the facial positions detecting unit, be used to use from the subject image that photographing optical system is caught and carry out the picture signal that the imageing sensor of opto-electronic conversion obtains, detect in the picture position that people's face at least exists; The focal point control unit is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture; Control module is used for controlling the focusing position that obtains the second focus detection zone that focusing position that described focal point control unit obtains with reference to the first focus detection zone that exists at described people's face at least or the health of estimating described people from the position judgment of described people's face exist; And judging unit, be used for judging in the described first focus detection zone and can focus on described people reliability on the face, described control module is based on the judged result of described judging unit, controls focusing position that described focal point control elements reference obtains or with reference to the focusing position that obtains in the described second focus detection zone in the described first focus detection zone.

According to a second aspect of the invention, a kind of focus adjusting apparatus comprises: the facial positions detecting unit, be used to use from the subject image that photographing optical system is caught and carry out the picture signal that the imageing sensor of opto-electronic conversion obtains, detect in the picture position that people's face at least exists; The focal point control unit is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture; And control module, be used for controlling the focusing position that obtains the second focus detection zone that focusing position that described focal point control unit obtains with reference to the first focus detection zone that exists at described people's face at least or the health of estimating described people from the position judgment of described people's face exist, if the difference of the focusing position in focusing position in the described first focus detection zone and the described second focus detection zone is equal to or less than predetermined value, then described control module is controlled the focusing position that described focal point control elements reference obtains in the described first focus detection zone.

According to a third aspect of the invention we, a kind of focus adjusting apparatus comprises: the facial positions detecting unit, be used to use from the subject image that photographing optical system is caught and carry out the picture signal that the imageing sensor of opto-electronic conversion obtains, detect in the picture position that people's face at least exists; The focal point control unit is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture; Control module is used for controlling the focusing position that obtains the second focus detection zone that focusing position that described focal point control unit obtains with reference to the first focus detection zone that exists at described people's face at least or the health of estimating described people from the position judgment of described people's face exist; And display unit, be used to show the image that obtains from described imageing sensor, if described focal point control unit is by controlling described photographing optical system with reference to the focusing position in described first focus detection zone or the described second focus detection zone, then described focal point control unit focuses on by the detected facial positions of described facial positions detecting unit and shows.

According to a forth aspect of the invention, a kind of focus adjusting method may further comprise the steps: facial positions detects step, be used to use from the subject image that photographing optical system is caught and carry out the picture signal that the imageing sensor of opto-electronic conversion obtains, detect in the picture position that people's face at least exists; The focal point control step is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture; Controlled step, be used to control, so that the focusing position that obtains the second focus detection zone that in described focal point control step, exists with reference to the focusing position that obtains in the first focus detection zone that exists at described people's face or the health of estimating described people from the position judgment of described people's face at least; And determining step, be used for judging in the described first focus detection zone and can focus on described people reliability on the face, described controlled step is controlled based on the judged result of described determining step, so that described focal point control step is with reference to the focusing position that obtains in the described first focus detection zone or with reference to the focusing position that obtains in the described second focus detection zone.

According to a fifth aspect of the invention, a kind of focus adjusting method may further comprise the steps: facial positions detects step, be used to use from the subject image that photographing optical system is caught and carry out the picture signal that the imageing sensor of opto-electronic conversion obtains, detect in the picture position that people's face at least exists; The focal point control step is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture; And controlled step, be used to control, so that the focusing position that obtains the second focus detection zone that in described focal point control step, exists with reference to the focusing position that obtains in the first focus detection zone that exists at described people's face or the health of estimating described people from the position judgment of described people's face at least, if the difference of the focusing position in focusing position in the described first focus detection zone and the described second focus detection zone is equal to or less than predetermined value, then described controlled step is controlled described focal point control step with reference to the focusing position that obtains in the described first focus detection zone.

The 6th invention according to this aspect, a kind of focus adjusting method may further comprise the steps: facial positions detects step, be used to use from the subject image that photographing optical system is caught and carry out the picture signal that the imageing sensor of opto-electronic conversion obtains, detect in the picture position that people's face at least exists; The focal point control step is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture; Controlled step, be used to control, so that the focusing position that obtains the second focus detection zone that in described focal point control step, exists with reference to the focusing position that obtains in the first focus detection zone that exists at described people's face or the health of estimating described people from the position judgment of described people's face at least; And step display, be used to show the image that obtains from described imageing sensor, if described focal point control step by controlling described photographing optical system with reference to the focusing position in described first focus detection zone or the described second focus detection zone, then focuses in described focal point control step in described facial positions and detects in the step detected facial positions and show.

According to a seventh aspect of the invention, a kind of focus adjusting apparatus comprises: face-detecting unit, be used to use the picture signal of carrying out the imageing sensor acquisition of opto-electronic conversion from the subject image that photographing optical system is caught, detect the facial position that exists of subject at least; Focus detecting unit is used at a plurality of focusing positions of estimating to detect with the focus detection zone that is existed by the facial corresponding health of the detected described subject of described face-detecting unit described photographing optical system; And control module, be used at least one focusing position of obtaining based in described focus detection zone, control moving of described photographing optical system, described control module is controlled, so as with described photographing optical system move to by in the detected described a plurality of focusing positions of described focus detecting unit with the corresponding focusing position of maximum distance.

According to an eighth aspect of the invention, a kind of focus adjusting apparatus comprises: face-detecting unit, and be used to use subject image to carry out the picture signal that opto-electronic conversion obtains by photographing optical system is caught, detect the facial information of subject; Estimation unit is used for from the detected described facial information of described face-detecting unit, estimates the subject distance; Focus detecting unit is used for detecting the focusing position of described photographing optical system based on described picture signal; And control module, be used to control so that described photographing optical system is moved to detected focusing position, if detect a plurality of focusing positions, then described control module is based on estimated subject distance, selects the focusing position that will move to described photographing optical system from described a plurality of focusing positions.

According to a ninth aspect of the invention, a kind of control method of focus adjusting apparatus may further comprise the steps: face detection step, be used to use subject image to carry out the picture signal that opto-electronic conversion obtains, detect the facial position that exists of subject at least by photographing optical system is caught; The focus detection step is used for detecting a plurality of focusing positions of described photographing optical system in estimating the focus detection zone that exists with the facial corresponding health of the detected described subject of described face detection step; And controlled step, be used at least one focusing position of obtaining based in described focus detection zone, control moving of described photographing optical system, described controlled step is controlled, so that described photographing optical system is moved in described focus detection step in detected described a plurality of focusing positions and the corresponding focusing position of maximum distance.

According to the tenth aspect of the invention, a kind of control method of focus adjusting apparatus may further comprise the steps: face detection step, be used to use subject image to carry out the picture signal that opto-electronic conversion obtains, detect the facial information of subject by photographing optical system is caught; Estimating step is used for estimating the subject distance from the detected described facial information of described face detection step; The focus detection step is used for detecting the focusing position of described photographing optical system based on described picture signal; And controlled step, be used to control, so that described photographing optical system is moved to detected focusing position, if detect a plurality of focusing positions, then described control module is based on estimated subject distance, selects the focusing position that will move to described shooting optical imagery from described a plurality of focusing positions.

According to an eleventh aspect of the invention, a kind of focus adjusting apparatus comprises: the facial positions detecting unit, be used to use from the subject image that photographing optical system is caught and carry out the picture signal that the imageing sensor of opto-electronic conversion obtains, detect in the picture position that people's face at least exists; Focus detecting unit, be used for first focus detection zone that detected described people's face by described facial positions detecting unit exists and estimate with at least one of the second focus detection zone of the corresponding described people's of detected described people's appearance health existence by described facial positions detecting unit in, detect the focusing position of described photographing optical system; And control module, be used for based at least one focusing position from described first focus detection zone and the acquisition of described second focus detection zone, control moving of described photographing optical system, wherein, the second focus detection zone is greater than the described first focus detection zone.

By following (with reference to the accompanying drawing) explanation to exemplary embodiments, further feature of the present invention will be apparent.

Description of drawings

Fig. 1 is the block diagram that illustrates according to the structure of the digital camera of first embodiment of the invention.

Fig. 2 A and 2B are the process flow diagrams of whole operations that the digital camera of first embodiment is shown.

Fig. 3 is shown specifically the photometry among Fig. 2 A and the 2B and the process flow diagram of focus detection program.

Fig. 4 is the figure that the example of focus detection frame is shown.

Fig. 5 is the figure that an example of the relation between focusing lens position and AF (auto focus, the automatic focusing) evaluation value signal is shown.

Fig. 6 is the figure that is used to explain the notion that the reliability of AF evaluation value signal is judged.

Fig. 7 is the process flow diagram that the AF process among first embodiment is shown.

Fig. 8 is used to illustrate and the process flow diagram of confirming to the operation of the rare pass of monotone decreasing of maximum focal length.

Fig. 9 is used to illustrate and the process flow diagram of confirming to the operation of the rare pass of monotone decreasing of minimum focus.

Figure 10 is the block diagram of structure that the picture pick-up device of second embodiment is shown.

Figure 11 is the process flow diagram of operation of the picture pick-up device of expression second embodiment.

Figure 12 is the process flow diagram of the subroutine of the AF operation among Figure 11.

Figure 13 A～13C is the figure that the example of facial detection position and AF position is shown.

Figure 14 is the process flow diagram of the subroutine of the shooting operation among Figure 11.

Figure 15 is the figure that the evaluation of estimate when detecting a plurality of focusing lens focusing position in single focus detection zone is shown.

Embodiment

Below be with reference to the accompanying drawing the following detailed description of the embodiment of the present invention.

First embodiment

Fig. 1 illustrates the block diagram of structure that use face detection function according to first embodiment of the invention carries out the picture pick-up device 100 of automatic focusing.In the present embodiment, use digital camera example as an illustration.

Among Fig. 1, Reference numeral 101 is the objective lens (object lens group) that are used to catch the subject image on the imageing sensor 103 described below, and Reference numeral 102 is the light quantity conditioning equipments that are provided with aperture (aperture stop) equipment and fast door equipment.Reference numeral 103 is to be used for the subject image transitions that objective lens 101 is caught is become CDD, the CMOS of electric signal or the imageing sensor of other type.Reference numeral 104 is to be used for the analog signal processing circuit that clamp (clamping) and gain (gaining) etc. are handled is carried out in the simulating signal output of imageing sensor 103.Reference numeral 105 is analog/digital (hereinafter referred to as " the A/D ") converters that are used for the output of analog signal processing circuit 104 is converted to digital signal.Pass through digital signal processing circuit 107 described below and memorizer control circuit 106 from the data of A/D converter 105 outputs, or directly by memorizer control circuit 106, and be written to storer 108.

Reference numeral 107 is to carry out the digital signal processing circuit that picture element interpolation and color conversion etc. are handled from the data of A/D converter 105 or memorizer control circuit 106.Digital signal processing circuit 107 uses the data from A/D converter 105, with the value of the focus state that calculates brightness value or expression subject and regulate white balance.

System, control circuit 112 is carried out control based on the result of calculation of digital signal processing circuit 107 to exposure control circuit 113 and focal point control circuit 114.Particularly, the subject image that system, control circuit 112 uses by objective lens 101 carries out focal point control processing, exposure control and treatment and light adjusting and handles.System, control circuit 112 has the display control circuit 117 of the demonstration that is used to control display device 110.

Memorizer control circuit 106 control analog signal processing circuits 104, A/D converter 105, digital signal processing circuit 107, storer 108 and digital-to-analog (hereinafter referred to as " D/A ") converter 109.The A/D data converted of having passed through in the A/D converter 105 is passed through digital signal processing circuit 107 and memorizer control circuit 106, the A/D data converted of perhaps having passed through in the A/D converter 105 is directly passed through memorizer control circuit 106, and is written to storer 108.

The data that are shown to display device 110 are write storer 108, and will write via D/A converter 109 on the described below display device 110 of data presentation of storer 108.Rest image or moving image that storer 108 storages are caught.Storer 108 can also be as the workspace of system, control circuit 112.

Reference numeral 110 is the display devices that constitute from by the LCD monitor of taking the image that the view data that obtained generates by being used to show, if show the subject image that uses imageing sensor 103 to obtain successively, then display device 110 is as electronic viewfinder.Display device 110 can be according to the order of system, control circuit 112, opens and closes arbitrarily to show, compares with opening when showing, the power consumption of closing picture pick-up device 100 when showing reduces.Display device 110 is according to the order of system, control circuit 112, uses character, image etc. to show the duty, message etc. of picture pick-up devices 100.

Reference numeral 111 is to be used for peripheral unit exchange image data such as storage card, hard disk and other exterior storage medium and computing machine and printer with about the interface of the management information of view data.If interface 111 meets pcmcia card, CF (CompactFlash ^TM, compact flash) and standard such as card and constituting, then interface 111 can be directly connected to various types of communication cards.This communication card comprises LAN card, nextport modem card NextPort, USB card, IEEE 1394 cards, P1284 card, SCSI card, PHS and other communication card etc.

Reference numeral 116 is the orientation detection circuit that detect the orientation of picture pick-up device 100 and testing result is exported to system, control circuit 112.

Whole operations of system, control circuit 112 control picture pick-up devices 100.Storer (not shown) storage in the system, control circuit 112 is used for the constant, variable, program of the operation of system, control circuit 112 etc.

Exposure control circuit 113 drives the diaphragm apparatus and the fast door equipment of fader control equipment 102.Focusing lens and zoom lens that focal point control circuit 114 drives in the objective lens 101.

By system, control circuit 112 and focal point control circuit 114 control automatic focusing operations.At first, detect facial positions by facial testing circuit 120.The characteristic of facial testing circuit 120 registered in advance people faces, and by comparing people's face in the recognition image data with this characteristic.In the present embodiment, facial testing circuit 120 is from the data of A/D converter 105 or write in the data of storer 108, partly detects people's face by the facial characteristics that detects as the eyes of characteristic registration and mouth etc.In this case, obtain facial positions and size information.

Then, portion's 121 focus detection frames that are provided with as described below are set by the focus detection frame, and by the focusing lens in the focal point control circuit 114 driving objective lens 101.In mobile focusing lens, the picture signal of catching in each focus detection zone that AF evaluation of estimate calculating part 122 uses in a plurality of focus detection zone is calculated and the corresponding signal of picture contrast.Then, focusing position determination portion 123 is determined focusing position, controls focusing lens and focusing lens are urged to this position, and show the focusing frames by focusing frame display part 124.When operating in the switch SW opened when partly pressing release-push 1 (131), the operation of focusing when operating in the switch SW opened when pressing release-push fully 2 (132), is caught and memory image.

The following calculating of carrying out the AF evaluation of estimate.Horizontal bandpass filter is applied to each row in the view data in the focus detection frame.Then, for each row, select to have the logical output signal of band of maximum value.Selected signal is carried out vertical integration.By this processing, detect the maximum horizontal contrast, and, obtain to have improved the signal of S/N than (signal to noise ratio (S/N ratio)) by carrying out vertical integration.This signal has maximal value when focusing, and defocuses along with image becomes, and this signal has the value that diminishes gradually.Therefore, the maximum value position by detecting this signal is also taken in this position, can obtain focus image.

Below, with reference to the main operation of the picture pick-up device of the flowchart text present embodiment among Fig. 2 A and the 2B.Note, will be used for carrying out the storer of the procedure stores of this processing, and under the control of system, control circuit 112, carry out this program at system, control circuit 112.

Fig. 2 A and 2B are the process flow diagrams that is used to illustrate according to the operation during the main processing of the picture pick-up device 100 of present embodiment.

For example, opening power promptly begins this processing after changing battery, at step S101, and various signs in the system, control circuit 112 initialization internal storages and control variable etc.

At step S102, system, control circuit 112 makes the default setting of the image demonstration in the display device 110 for closing (off).

At step S103, system, control circuit 112 detects whether selected screening-mode, under screening-mode, to being provided with by picture pick-up device 100 shootings and storing image data.If screening-mode is not set, then handles and enter step S104.At step S104, system, control circuit 112 is carried out according to the selected pattern that is different from screening-mode and is handled, and turns back to step S103 after finishing this processing.

If be provided with screening-mode in step S103, then system, control circuit 112 enters step S105, judges whether the dump energy of power supply or working condition have problems for the operation of picture pick-up device 100.If the existing problems of judging, then system, control circuit 112 enters step S107, uses display device 110 to show by image or sound and specifies warning, turns back to step S103 then.

At step S105, do not have problems if judge power supply, then system, control circuit 112 enters step S106.At step S106, whether the working condition that system, control circuit 112 is judged storage medium especially has problems data recording to storage medium or from the operation of storage medium replay data for the operation of picture pick-up device 100.If the existing problems of being judged as, then system, control circuit 112 enters above-mentioned steps S107, uses display device 110 to show by image or sound and specifies warning, turns back to step S103 then.

Do not have problems if be judged as in step S106, then system, control circuit 112 enters step S108.At step S108, system, control circuit 112 uses display device 110, shows the user interface (hereinafter referred to as " UI ") of the setting of picture pick-up device 100 by image or sound.Note, open (on) if the image of display device 110 is shown as, the UI that then can use display device 110 to carry out the various settings of the picture pick-up device 100 by image or sound shows.Thereby be provided with by the user.

Then, at step S109, system, control circuit 112 is arranged to the image demonstration of display device 110 to open.

In addition, at step S110, system, control circuit 112 is arranged to observe display mode with picture pick-up device 100, and feasible order shows the image that generates based on the view data that imageing sensor 103 obtained.Observing under the display mode, the data of order being write storer 108 are shown to display device 110 in proper order, and therefore, display device 110 is as electronic viewfinder.

At step S114, system, control circuit 112 checks whether supress shutter release SW1, if do not press, then turns back to step S103, if supress shutter release SW1, then enters step S115.

At step S115, system, control circuit 112 makes exposure control circuit 113 control that exposes, so that the brightness value of picture is correct.If desired, can the flash device (not shown) be glistened during taking according to the result of the exposure control of this moment.In addition, make focal point control circuit 114 carry out focal point control, so that the zone that people's face exists is in focusing state.

At step S116, system, control circuit 112 is kept the observation display mode, till having operated shutter release SW2.

Then,, under the situation of not pressing shutter release SW2, discharged shutter release SW1, then handled turning back to step S103 if detect at step S117.

On the other hand, if in step S117, supress shutter release SW2, then handle and enter step S119.

At step S119, system, control circuit 112 is used for the view data of being caught is write the photographing process of storer 108.Exposure control circuit 113 drives diaphragm apparatus according to the control of the exposure among step S115 result, and makes imageing sensor 103 exposures by opening shutter.Flash device is glistened,, then close shutter in case passed through the set time shutter.By A/D converter 105, digital signal processing circuit 107 and memorizer control circuit 106, will write storer 108 as the view data that is used to preserve from the charge signal of imageing sensor 103 outputs.System, control circuit 112 further uses memorizer control circuit 106 and digital signal processing circuit 107, reads the view data that is used to preserve of writing storer 108 and carries out the vertical summation processing.Make digital signal processing circuit 107 carry out color successively and handle, generate the view data that is used to show and this view data is write storer 108 once more.

At step S120, display device 110 uses the view data that is used to show that obtains in step S119, show captured image.

At step S121, system, control circuit 112 reads the view data that is used to preserve of writing storer 108, and makes memorizer control circuit 106 and also has digital signal processing circuit 107 to carry out various Flame Image Process if necessary.Then, system, control circuit 112 carries out image Compression, and carries out the stores processor that the view data that is used to preserve after will compressing is write storage medium.

In case finished the stores processor among the step S121, at step S122, system, control circuit 112 checks whether supress shutter release SW2.If shutter release SW2 is in down state, then to handle and enter step S123, system, control circuit 112 is judged the internal storage of system, control circuit 112 or the state of the continuous shooting sign in the storer 108 of being stored in.Open (on) if continuous shooting is masked as, then system, control circuit 112 enters step S119 carrying out image capturing continuously, and catches next image.At step S123, if the continuous shooting sign is not opened, then system, control circuit 112 enters step S122, and the processing of repeating step S122 and S123 is till having closed shutter release SW2.

After the stores processor of step S121, if shutter release SW2 for closing, then handles from step S122 and enters step S124.At step S124, before entering step S125, handle and wait for, till the demonstration time of having passed through to captured image setting.

At step S125, system, control circuit 112 is arranged to observe display mode with display device 110, and enters step S126.Therefore, behind can be in the confirming display device 110 captured image, the observation display mode is set for take next time.

At step S126, system, control circuit 112 checks whether shutter release SW1 is in open mode, if then enter step S117 and prepare image capturing next time.At step S126,, then after finishing a series of images and catching operation, handle entering step S103 if shutter release SW1 is for closing.

Then, Fig. 3 is shown specifically the photometry of the step S115 among Fig. 2 B and the process flow diagram of focus detection program.

At first, when opening shutter release SW1 in the step S114 of Fig. 2 A, system, control circuit 112 makes exposure control circuit 113 control that exposes at step S301, so that the brightness value in the picture is correct.

Then, at step S303, facial testing circuit 120 carries out the detection of people's face.As everyone knows, as being used to detect facial technology many methods are arranged.For example, existing with neural network is the method for the use study of an exemplary.Also has the method for in view data, using template matches identification eyes, nose, mouth and face contour etc. to have the part of physical form feature.Except that these methods, detect the characteristic quantity in the view data such as the colour of skin and eye shape in addition and use the method for statistical study.(for example, referring to Japanese kokai publication hei H10-232934 communique or Japanese kokai publication hei 2000-48184 communique etc.) in addition, also has following method: judge that adjacent facial zone before is whether near detected zone, judge near the color the facial zone for the color of adding clothes, perhaps the position of more close picture central authorities is provided with lower being used to and discerns facial threshold value.Also have following method: the zone of specifying main subject to exist in advance, storage histogram and color information, and by asking correlation to follow the tracks of main subject.In the present embodiment, be used to detect pair of eyes, nose, mouth and face contour and determine the method for people's face, carry out face recognition processing based on its relative position.And, can also before opening SW1, begin periodically to detect people's face, and just read up-to-date facial testing result in case open SW1.

Then, at step S305, the focus detection frame is provided with portion 121 and at the body position from detected facial positions and facial size estimation the focus detection frame is set.For example, in Fig. 4, the AF frame that facial positions and the big or small former state from facial testing circuit acquisition can be used as facial positions.About body position, suppose under the face to have health, the frame with the identical size of facial frame size can adjacently be set under facial frame.And, although health is usually located at below the facial positions, detect the orientation of picture pick-up device by using orientation detection circuit shown in Figure 1 116, judge the direction downward with respect to facial positions.Alternatively, can detect the inclination of the face in the picture, detect the direction of health location afterwards.The focus detection frame of body position is configured to not overlapping with the focus detection frame of face.A reason that detects the focus failure at facial positions place is most of zone that the low colour of skin of brightness value difference has occupied facial positions, and is as described below, this means the AF evaluation of estimate that can not obtain to have high reliability.If the focus detection frame is arranged on body (health) position of having avoided facial positions, although then obtain to have the style that the AF evaluation of estimate of high reliability depends on clothes, its possibility increases.Equally, if be not to be provided with one but a plurality of focus detection frames are set to body position, the possibility of the focus detection frame that then can improving succeeds detects focus.

At step S307, AF evaluation of estimate calculating part 122 detects the focus of focus detection frame.

Then, at step S309, focusing position determination portion 123 judges whether successfully detect focus in the facial positions frame, if detected, then focal point control circuit 114 by the focusing position of reference faces position, drives focusing lens in step S311.If successfully do not detect focus, then focal point control circuit 114 by the focusing position with reference to the body position frame, drives focusing lens at step S313.Even, then focusing lens are driven into default location if also successfully do not detect focus at the body position place.If all successfully detected focus, can consider that then two focusing positions drive focusing lens at the frame of facial positions and the frame place of body position.Notice for example, whether the minimum value that can be by judging AF evaluation of estimate during the focus detection and the difference of maximal value are equal to or greater than designated value, judge whether to detect focus.Below this is described in detail.

And, if in picture, detect a plurality of faces, then each face and health are carried out focus detection.

After driving focusing lens, at step S315, focusing frame display part 124 shows the focusing display box as shown in Figure 4 on facial detection position.Under the situation of the camera that is equipped with face detection function, if successfully detecting face and judging to focus on the people, then show and compare with locational focusing by distance (arrive health etc.) actual measurement, the focusing demonstration on the facial positions make the user easier know focus on the people.The user is clear to focus on people's the health in order to make, and the demonstration that is different from the focus detection frame of facial positions can also be shown to the part of people's health.

Then, at step S317, focus on the subject, system, control circuit 112 makes exposure control circuit 113 control that exposes once more, so that the brightness value of picture is correct.Then, system, control circuit 112 turns back to the master routine among Fig. 2 A and the 2B.

Then, illustrate and be used for judging whether that at the step S309 of Fig. 3 success detects the method for focus.

In the step S307 of Fig. 3, system, control circuit 112 carries out scan A F (auto focus, automatic focusing) in order to detect focusing position to be handled.Use Fig. 5 to provide the summary that scan A F handles.Scan A F is carried out in the position of the focusing lens that the high fdrequency component of exporting by the picture signal that obtains to be generated by imageing sensor 103 is the highest.System, control circuit 112 moves to the position (" B " among Fig. 5) that is equivalent to minimum focus set under each screening-mode with focusing lens from the position (" A " Fig. 5) that is equivalent to maximum focal length.When driving focusing lens, acquisition is from the output (AF evaluation value signal) of AF evaluation of estimate calculating part 122, from the AF evaluation value signal that has obtained in case finished the driving of focusing lens, obtain the highest position (" C " among Fig. 5) of AF evaluation value signal, and focusing lens are driven into this position.

For accelerated scan AF handles, do not carry out the output that obtains AF evaluation of estimate calculating part 122, and only carry out this acquisition in given step in all rest position of focusing lens.In this case, obtain the AF evaluation value signal at some a1, a2 shown in Figure 5 and a3 place.In this case, obtain focusing position C based on AF evaluation value signal the highest point and the point before and after this point by calculating.And, below will be called " analyzing spot " in the focusing lens position of each given step acquisition AF evaluation value signal, in the present embodiment, the analyzing spot at maximum focal length place is 0, the analyzing spot at minimum focus place is N.

In the present embodiment, carrying out interpolation and obtaining the highest point (C among Fig. 5) of AF evaluation value signal before, estimate the reliability of AF evaluation value signal.If reliability is abundant, then obtains the highest point of AF evaluation value signal, and judge that focusing detects successfully.

As the result of the reliability of estimating the AF evaluation value signal, if reliability is low, then do not carry out processing, and judge that focusing detects not success in order to the highest point of acquisition AF evaluation value signal.

Then, describe the method for the reliability of the AF evaluation value signal be used for judging that scan A F handles in detail.

Except that the special circumstances of maximum focal length and minimum focus contradiction, the AF evaluation value signal has chevron as shown in Figure 6, and wherein transverse axis is a distance, and Z-axis is the AF evaluation of estimate.Therefore, in the present embodiment, consider the minimum value of AF evaluation value signal and maximal value poor, with the length of the part of the slope inclination that is equal to or greater than a certain fixed value and the slope of sloping portion, whether have the reliability that chevron is judged the AF evaluation value signal by judging the AF evaluation value signal.

As shown in Figure 6, in the present embodiment, some P2 and some P3 that declivity that acquisition (is put P1) from the hilltop obtains, point P2 and the width of point between the P3 are the width L on mountain, and the difference SL2's of the difference SL1 of the AF evaluation of estimate at some P1 and some P2 place and the AF evaluation of estimate at some P1 and some P3 place is the height SL on mountain with (being SL1+SL2).

Below, provide the explanation of concrete operations of judging the reliability of AF evaluation value signal according to the process flow diagram in Fig. 7～9 with reference to Fig. 6.

At first, at step S701, obtain from the maximal value max and the minimum value min of the AF evaluation of estimate of AF evaluation of estimate calculating part 122 outputs and provide this peaked analyzing spot io.At step S702, the variable SL of the height on the variables L of the width on the mountain of expression AF evaluation of estimate and this mountain of expression all is initialized to 0.

Then, inspection provides peaked analyzing spot io and whether is in the position that is equivalent to maximum focal length, perhaps in other words, whether check io=0, if this analyzing spot io is in the position (being "Yes" among the step S703) that is equivalent to maximum focal length, then skips steps S704 handles entering step S705.On the other hand,, then handle and enter step S704, check that the dullness to the focusing lens position that is equivalent to maximum focal length reduces if this analyzing spot io (is "No") not in the position that is equivalent to maximum focal length among the step S703.

Referring now to the processing that is used among the flowchart text step S704 among Fig. 8 check to the dullness minimizing of the focusing lens position that is equivalent to maximum focal length.

At first, at step S801, i is initialized to io with counter variable.Then, with the value d[i of AF evaluation of estimate] with from the value d[i-1 of i to the AF evaluation of estimate of the analyzing spot i-1 of the nearlyer analyzing spot of maximum focal length] compare (given step).If d[i] greater than d[i-1] (being "Yes" among the step S802), then being judged as generation reduces to the dullness of maximum focal length, processing enters step S803, upgrades the variable SL of the height on the variables L of width on mountain of expression AF evaluation of estimate and this mountain of expression according to following formula.

L＝L+1

SL＝SL+(d[i]-d[i-1])

Then, at step S802, if d[i]＞d[i-1] be not true, then be judged as the dullness that does not take place to maximum focal length and reduce, be used to check finishing dealing with that dullness to maximum focal length reduces, and handle and enter step S705.

After the processing in step S803, handle and enter step S804, at step S804, i=i-1, the point that will be used to detect moves an analyzing spot to maximum focal length.

At step S805 and S806, with L and SL and can think comparing of mountain, and judge whether they are equal to or greater than threshold value about the threshold value Lo of the width on this mountain with about the threshold value SLo of the height on this mountain.If they are equal to or greater than threshold value, then satisfied the condition of processing of reliability that is used to judge the AF evaluation of estimate of in the step S708 of Fig. 7 and S709, carrying out of the following stated, therefore be not used to check processing, and processing enters step S705 to the dullness minimizing of maximum focal length.

Be under the situation of "No" in step S805 or S806, handle entering step S807, check whether counter i has reached the value (=0) that is equivalent to maximum focal length.If the value of counter i is not 0, then handles and turn back to step S802, and repeat above the processing.If the value of counter i is 0, perhaps in other words,, then is used to check finishing dealing with that dullness to maximum focal length reduces, and handles and enter step S705 if analyzing spot has reached the position of maximum focal length.

Therefore, begin to check that from i=io the dullness to maximum focal length reduces.

If in step S704, be used to check finishing dealing with that dullness to maximum focal length reduces, check then then whether the analyzing spot io that provides maximal value max is in the position of the minimum focus (N) that is equivalent to be used to carry out scan A F, if this analyzing spot io is in the position (being "Yes" among the step S705) that is equivalent to minimum focus, then skips steps S706 handles entering step S707.On the other hand,, then handle and enter step S706, check that the dullness to the focusing lens position that is equivalent to minimum focus reduces if this analyzing spot io (is "No") not in the position that is equivalent to minimum focus among the step S705.

Referring now to the processing that is used among the flowchart text step S706 among Fig. 9 check to the dullness minimizing of the focusing lens position that is equivalent to minimum focus.

At first, at step S901, i is initialized to io with counter variable.Then, with the value d[i of the AF evaluation of estimate at analyzing spot i place] with from the value d[i+1 of i to the AF evaluation of estimate of the analyzing spot i+1 of the nearlyer analyzing spot of minimum focus] compare.If d[i] greater than d[i+1] (being "Yes" among the step S902), then being judged as generation reduces to the dullness of minimum focus, processing enters step S903, upgrades the variable SL of the height on the variables L of width on mountain of expression AF evaluation of estimate and this mountain of expression according to following formula.

L＝L+1

SL＝SL+(d[i]-d[i+1])

Then, at step S902, if d[i]＞d[i+1] be not true, then be judged as the dullness that does not take place to minimum focus and reduce, be used to check finishing dealing with that dullness to minimum focus reduces, and handle and enter step S707.

After the processing in step S903, handle and enter step S904, at step S904, i=i+1, the point that will be used to detect moves an analyzing spot to minimum focus.

At step S905 and S906, with L and SL and can think comparing of mountain, and judge whether they are equal to or greater than threshold value about the threshold value Lo of the width on this mountain with about the threshold value SLo of the height on this mountain.If they are equal to or greater than threshold value, then satisfied the condition of processing of reliability that is used to judge the AF evaluation of estimate of in the step S708 of Fig. 7 and S709, carrying out of the following stated, therefore be not used to check processing, and processing enters step S707 to the dullness minimizing of minimum focus.

Be under the situation of "No" in step S905 or S906, handle to enter step S907, check counter i whether reached the value that is equivalent to minimum focus (=N).If the value of counter i is not N, then handles and turn back to step S902, and repeat above the processing.If the value of counter i is N, perhaps in other words,, then is used to check finishing dealing with that dullness to minimum focus reduces, and handles and enter step S707 if analyzing spot has reached the position of minimum focus.

Therefore, begin to check that from i=io the dullness to minimum focus reduces.

If finished the inspection that reduces to the dullness of maximum focal length and minimum focus, will be used to then to judge that all coefficients and their threshold values separately of the reliability of AF evaluation of estimate compares, if satisfy all conditions, it is reliable then being judged as the AF evaluation of estimate.

At step S707, the maximal value max of AF evaluation of estimate and difference and the threshold value of minimum value min are compared, if should poorly then be judged as the shortage reliability less than threshold value, and processing enters step S711.Note, be provided with this threshold value lower, just can success so that only under the low really situation of contrast, detect.If the answer among the step S707 is a "Yes", then at step S708, will compare with the length L and the threshold value Lo of the part of the slope inclination that is equal to or greater than a certain fixed value, if length L is less than threshold value Lo, then be judged as the shortage reliability, and processing enters step S711.If the answer among the step S708 is a "Yes", then at step S709, highly SL and SLo compare, if SL, then is judged as the shortage reliability less than designated value, and processing enters step S711.

If satisfy all three above-mentioned conditions, then be judged as the AF evaluation of estimate and be reliably, and handle and enter step S710, the AF evaluation of estimate that calculates from AF evaluation of estimate calculating part 122 obtains to be used to drive the position of focusing lens.Calculate the position that is used to drive focusing lens by the highest position of AF evaluation of estimate that acquisition discrete calculation such as interpolation go out.

If it is unreliable and handle and to enter step S711 to judge the AF evaluation of estimate, then is judged as and does not successfully detect focus.

As mentioned above, according to top embodiment, even low and can not detect under the situation of focus,, also can focus on the people exactly even perhaps in the focus detection zone, mixed under the situation of the equidistant different subject of facial and background in the contrast of face.

Note, in the above embodiments,, then focusing lens are driven into the focusing position of facial positions if successfully detect focus at the facial positions place.Yet the focus detection result who has the facial positions place is owing to the influence that is subjected to background contrasts causes focus possibility too backward.For this reason, when only the difference of the focusing position at portion position and body position place is equal to or less than designated value face to face, the focus detection result that just can judge the facial positions place is correct, and focusing lens are driven into the focusing position of facial positions, if should be poor, then focusing lens can be driven into the focusing position of body position greater than designated value.

Note,, then also can for example carry out focus detection by the focus detection frame being set in picture central authorities if successfully do not detect face.

Second embodiment

Second embodiment below is described.

The simplified structure of digital camera

Figure 10 illustrates to use the focus figure of simplified structure of digital camera of operation of face detection function.

Digital camera has the photographing optical system that is made of optical system 1101 and focusing lens 1102 etc.The light (subject image) of catching by 1103 pairs of photographing optical system of imageing sensor carries out opto-electronic conversion.By Memory Controller 1106, will be by A/D converter 1105 and be provided with signal storage after pre-process circuit 1104 digitizings of the non-linear amplifying circuit that is used for eliminating output noise and CDS circuit at storer 1107.By signal processing circuit 1108 this conversion of signals is become image, and it is stored on the storage medium 1109.Note, the 1110th, be used for when catching image, showing the picture of being caught and AF frame (this frame illustrate with imageing sensor on corresponding zone, focus detection zone) and the operation display part that is used for display image and camera status information.By systems control division 1113 these demonstrations are totally shown control.The 1111st, be used to provide the switch (hereinafter referred to as " SW1 ") of taking the standby operation order, the 1112nd, be used for behind operation SW1, providing the shooting switch (hereinafter referred to as " SW2 ") of taking order.

By systems control division 1113 control focusing operations.At first, facial test section 1115 detects the facial information that comprises facial positions.About detecting facial method, can use known method.In this case, obtain facial positions and size information.Then, as described below, by the AF frame portion 1116 is set AF frame (the focus detection zone in the imageing sensor) is set, and move focusing lens 1102 by focusing lens driving circuit 1114.In mobile focusing lens, in AF evaluation of estimate calculating part 1117, use the picture signal of catching of catching to calculate the corresponding signal of contrast of catching picture signal (signal of expression focus state etc.) with this in place, a plurality of focusing lens position.Then, focusing position determination portion 1118 is determined focusing positions, and control focusing lens, and focusing lens are driven into this position are shown to operation display part 1110 by focusing frame display part 1119 frame of will focusing.Notice that carry out AF and other shooting standby operation by operation SW1, the operation of SW2 makes carries out the shooting and the storage of image.

The following calculating of carrying out the AF evaluation of estimate.Horizontal bandpass filter is applied to each row in the view data in the focus detection zone.Then, for each row, select to have the logical output signal of band of maximum value.Selected signal is carried out vertical integration.Utilize above structure, the maximum-contrast on the detection level direction, and vertical this contrast of integration obtains to have improved the signal of S/N ratio.This signal has maximal value under focusing state, and this value reduces under defocus condition.Therefore, be in its peaked focusing lens position and take, can obtain focus image in this position by detecting this signal.

The operational processes of digital camera

The following detailed description that provides the operation of digital camera with reference to the process flow diagram among Figure 11.

At first,, detect the state that is used for providing the main switch of power supply,, then handle entering step S1202 if main switch is opened to system's (not shown) at step S1201.At step S1202, check the residual capacity of storage medium 1109, if this residual capacity is 0 (zero), then handles and enter step S1203, if be not 0, then handle and enter step S1204.At step S1203, the residual capacity that storage medium 1109 is provided is 0 warning, and processing turns back to step S1201.Warning can be shown to operation display part 1110, also can warn, perhaps warn by the two by warning sound from the audio output part (not shown).

At step S1204, check the state of switch SW 1, if switch SW 1 is opened, then handle entering step S1206, if switch SW 1 is not opened, then handle entering step S1205.At step S1205, check the state of main switch (not shown), if main switch is opened, then handle entering step S1204, if main switch is not opened, then handle entering step S1201.At step S1206, carry out AE and handle, at step S1207, carry out the AF operation according to the process flow diagram among Figure 12 of the following stated.At step S1208, check the state of SW2, if SW2 opens, then handle and enter step S1210, if SW2 does not open, then handle and enter step S1209.At step S1209, check the state of SW1, if SW1 opens, then handle and turn back to step S1208, if SW1 does not open, then handle and enter step S1204.At step S1210, carry out shooting operation according to the process flow diagram among Figure 14 of the following stated.At step S1211, check the residual capacity of storage medium 1109, if residual capacity is 0 (zero), then handles and enter step S1203, if residual capacity is not 0, then handles and enter step S1212.At step S1212, check the state of SW2, if SW2 does not open, then handle and enter step S1209.

Only detect an AF operation when facial

AF function subprogram among the step S1207 of following process flow diagram with reference to the flowchart text Figure 11 among Figure 12.

At step S1301, carry out face by facial test section 1115 and detect.At step S1302, determine the size of AF frame by detected facial size, and, a plurality of AF frames are set in detected facial positions with along in the possible range in the shooting picture of predicting the perpendicular line direction that the pairing health of this facial positions exists.

For example, as shown in FIG. 13A, about facial positions, the size that the facial positions that is obtained at facial test section 1115 is sentenced this face is provided with the AF frame.In addition, along the perpendicular line direction that begins from the facial positions of predicting the health location, a plurality of AF frames of the identical size of AF frame that will install with the position, opposite form a line, and if possible, are provided with down to the chest of this facial subject and a plurality of AF frames of belly position.

At this moment, according to the position and the size of detected face, the direction that can not exist along the pairing health of facial positions in the prediction shooting picture is provided with the AF frame, therefore only at the facial positions place AF frame is set.

At step S1303, with the corresponding focus detection of AF frame zone in carry out focus detecting operation.At step S1304, judge for whether successfully having obtained focusing position by the focus in the corresponding focus detection of the AF frame zone at detection and facial positions place.If successfully obtained focusing position, then at step S1305, with focusing lens move to the corresponding focus detection of facial positions AF frame zone in focusing position, if successfully do not obtain focusing position, then handle entering step S1306.At step S1306, whether the direction that exists along the pairing health of prediction facial positions in step S1302 is provided with the AF frame checks.If the direction that exists along the facial pairing health of prediction is provided with the AF frame, then handle entering step S1309, if only the AF frame is set to facial positions, then handles and enter step S1307.At step S1309, check whether being provided with a plurality of AF frames along the direction of predicting the pairing health existence of the facial positions that has successfully obtained focusing position, if there are a plurality of AF frames, then handle and enter step S1310, at step S1310, carry out focus detection, and focusing lens are moved to more focusing position away from subject from corresponding focus detection zone.If there is no a plurality of AF frames are then handled and are entered step S1311.At step S1311, to with the direction that exists along the pairing health of prediction facial positions on the corresponding focus detection of any one AF frame zone in whether successfully obtained focusing position inspection, if successfully obtained focusing position, then in step S1312, focusing lens are moved to the focusing position that is obtained.If with the corresponding focus detection of any one AF frame zone in successfully do not obtain focusing position, then handle entering step S1307, focusing lens are moved to the position that sets in advance that is called as point of fixity, and in step S1308, do not focus on demonstration.

At step S1313, in the demonstration of focusing of facial inspection positions.Under the situation of the camera that is equipped with face detection function, can carry out face and detect if judge, and can detect focusing position, the demonstration of then focusing in the facial positions of subject or adjacent position under facial positions at the facial positions place.This is because show to the focusing of the position (zone of health etc.) of focus with actual detected and to compare, the focusing at facial positions place show feasible easier know focus on people's (subject of expection).

Notice for example, whether the minimum value that can be by judging AF evaluation of estimate during the focus detection and the difference of maximal value are equal to or greater than designated value, judge whether to obtain focusing position.

By using said structure, even there is the barrier of closer distance as shown in FIG. 13A at the body position place of detected facial subject, and can not carry out AF at the facial positions place, also can focus on the facial subject.

Shooting operation

Shooting operation subroutine among the step S1210 of following process flow diagram with reference to the flowchart text Figure 11 among Figure 14.

At first, at step S1501, measure the brightness of subject.At step S1502, the subject brightness according to measured in step S1501 exposes on imageing sensor 1103.The image of catching on the surface of imageing sensor 1103 is carried out opto-electronic conversion and becomes simulating signal, at step S1503 this simulating signal is sent to A/D converter 1105, after having eliminated, this analog signal conversion is become digital signal from pre-service such as the output noise of imageing sensor 1103 and Nonlinear Processing.At step S1504, by signal processing circuit 1108, make output signal become correct output image signal from A/D converter 1105, at step S1505, output image signal is converted to the picture format of jpeg format etc., and, this output image signal is transmitted and stores in the storage medium 1109 at step S1506.

Thereby realized following structure: even, also can obtain focusing position by AF frame (focus detection zone) is set in the position that does not comprise detected face not regulating under the situation of focus because facial contrast is too low.Detecting focus,, also focal adjustments can be arrived detected facial subject by by this way even facial contrast is too low according to the detected facial body position place of measuring.Even there is nearer barrier in the body position in detected facial subject, also can focus on the subject of expection and not with focal adjustments to barrier.

Notice that in the above description, the subject of expection is described the adult, but be not limited to this.For example, it will also be appreciated that the situation of from background, cutting the subject image.In this case, subject can be the subject beyond the people, the size of known this subject to a certain extent wherein, and known detected zone of cutting is with the position of this subject of exterior domain.

In the above description, used following structure: when successfully detecting focus at the facial positions place, not with reference to the direction that exists along the pairing health of prediction facial positions on the corresponding focus detection of a plurality of AF frames zone in focus detection result.Yet the two estimates the focusing position of focusing lens as a result also can to use the focus detection result at facial positions place and the focus detection of the position that the pairing health of prediction facial positions exists.

Detect the AF operation under the situation of a plurality of faces

AF operation when then, detecting a plurality of face with reference to the flowchart text among Figure 12.A plurality of methods that the AF frame is set during by facial test section 1115 detected facial positions are different with above method when existing.Others are identical, thereby omit the explanation to its operation.

At step S1301, carry out face by facial test section 1115 and detect.Exist under the situation of two or more detected faces, carrying out the interarea portion selection processing that is used to select face (interarea portion) as main subject.Consider about the past as the reliability of the accuracy of the information of the face of interarea portion, the detected face of expression, facial size and facial positions etc., carry out selection as the face of interarea portion.Obtain two out of Memory: about as the information of the face of main subject with about the information of other detected face.

When detecting a plurality of face, face as much as possible is provided with the AF frame and detects focus state, thereby make whether easier inspection focuses on the subject of user's expection.Therefore, at step S1302, at first, determine the size of AF frame based on interarea portion size.Then, the perpendicular separation and the horizontal interval of AF frame are set, thereby preferentially locate the AF frame of other a plurality of detected faces.Then, the direction that exists along the pairing health of each detected facial positions of prediction is provided with the AF frame.At step S1303, with the corresponding focus detection of AF frame zone in carry out focus detecting operation.At step S1304, for by with the corresponding focus detection of the AF frame zone of interarea portion position in detect focus and whether successfully obtained focusing position and judge.If successfully obtained focusing position,, focusing lens are moved to focusing position with the corresponding focus detection location of AF frame of interarea portion position then at step S1305.If with the corresponding focus detection of the AF frame zone of interarea portion position in successfully do not obtain focusing position, then handle entering step S1306.

Notice that in the above description, the subordinate frame in interarea portion and the interarea portion (AF result) is the focus detection result's of focusing lens control period institute reference a object, and the frame of the face beyond the interarea portion only is used for the decision demonstration of whether focusing.

In this case, if the interval of AF frame is arranged to 0, the position that then usually will adjacent AF frame of under facial positions, locating be set to the neck of facial subject, and by focus detection obtain focusing position the result since with background distance contradiction frequently more away from the focusing position of facial subject.For this reason, make along the focus detection zone on the direction of the pairing health existence of the prediction facial positions relevant with this face to be downward 2 the AF frame (skipping 1) of facial positions AF frame, this focus detection zone is corresponding to following again 1 the AF frame of facial positions AF frame (Figure 13 B).Under spaced situation between the AF frame, make focus detection zone on the direction that exists along the pairing health of the prediction facial positions relevant with this face be with adjacent under facial positions AF frame and the AF frame corresponding focus detection zone adjacent with facial positions AF frame, this focus detection zone is corresponding to adjacent AF frame (Figure 13 C) under facial positions AF frame.

At step S1306, whether be provided with the AF frame for the direction that in step S1302, exists and check along the prediction interarea portion pairing health in position.If the position that exists at the pairing health of prediction interarea portion is provided with the AF frame, then handle and enter step S1309, if only the AF frame is set to facial positions, and the AF frame is not set to the position that the pairing health of prediction interarea portion exists, then handles entering step S1307.At step S1309, to whether existing a plurality of AF frames to check along the direction of predicting the pairing health existence in the interarea portion position that has successfully obtained focusing position.If there are a plurality of AF frames, then handle and enter step S1310, carry out focus detection, and focusing lens are moved to and the corresponding focus detection zone middle distance subject of these a plurality of AF frames focusing position farthest, wherein these a plurality of AF frames are corresponding to a plurality of AF frames that successfully obtained focusing position.If there is no a plurality of AF frames are then handled and are entered step S1311.At step S1311, carry out with the corresponding focus detection of one of them the AF frame zone of the direction that exists along the prediction interarea portion pairing health in position in whether successfully obtained the inspection of focusing position.If successfully obtained focusing position, then in step S1312, focusing lens are moved to the focusing position that is obtained.Even if with the direction that exists along the prediction interarea portion pairing health in position on the corresponding focus detection of any one AF frame zone in all successfully do not obtain focusing position, then handle entering step S1307.Focusing lens are moved to the position that sets in advance that is called as point of fixity, and do not focus on demonstration at step S1308.

At step S1313, in the demonstration of focusing of interarea portion inspection positions.Under the situation of the camera that is equipped with face detection function, can carry out the face detection if judge, and can detect focusing position, the demonstration of then focusing in the facial positions of main subject or adjacent position under the facial positions that the pairing health of prediction facial positions exists at the facial positions place.This is because show to the focusing of the position (body region etc.) of focus with actual detected and to compare, the focusing at facial positions place show feasible easier know focus on people's (subject of expection).When the focusing of carrying out interarea portion frame shows,, then also show facial frame focusing if the AF result's of the AF result of the AF frame of interarea portion and the AF frame relevant with the facial frame beyond the interarea portion difference is in the predetermined depth.

Carry out focus detection and focusing demonstration by aforesaid control, can clearly notify the user to focus on which subject.

In the above description, at first select interarea portion, carry out focal adjustments then, thereby focus on interarea portion (perhaps,, then focusing on the position that the pairing health of prediction interarea portion exists) if can not carry out focus detection in the interarea portion.Adopted in case reach the structure that focusing state is just focused and shown.Yet be not limited to this, can also adopt following structure: use AF frame shown in Figure 13 B and Figure 13 C to be provided with and the result of focus detection in farthest AF result, and regardless of they be interarea portion or other face.Can also adopt basis definite which the AF result's of use of priority of detected face structure in advance.

AF operation when the information used from facial size estimation subject distance

Then, illustrate in system of selection, use information from facial size estimation subject distance corresponding to the AF result in the focus detection zone of a plurality of AF frames relevant with interarea portion.Others are identical, thereby omit the explanation to its operation.

Then, in the step S1310 of the process flow diagram of above-mentioned Figure 12, adopt following structure: based on the AF result in focus detection zone, mobile focusing lens, wherein the AF frame of the interior distance of the pairing subject depth of field of estimated distance (field depth) that calculates of this focus detection zone and facial size from interarea portion, more close this estimated distance is corresponding.

According to facial test section 1115 detected facial sizes, this estimated distance of following acquisition.Suppose that the facial size of actual standard is Lstd, the size of detected facial zone is L on the image, and focal length is f, then can utilize d=f (1+Lstd/L) to obtain this estimated distance d.

In addition, suppose that the diameter of allowing blur circle (permissible circle of confusion) is , the f-number of optical system (Fstop) is F, then can utilize dB=dA+F δ dA2/ (f2-dAF δ) and dC=dA+F δ dA2/ (f2+dAF δ) obtain with respect to focusing enter from dA the rear of the degree of depth apart from dB and the place ahead apart from dC.

Therefore, suppose that the rear distance and the place ahead distance that enter the degree of depth with respect to estimated distance d that obtain from facial size are respectively db and dc, and corresponding to the AF result in the focus detection zone of a plurality of AF frames relevant with this face is dj (j=0,1, ..., N), then use following formula to judge.

dc＜dj＜db

By carrying out this judgement, in corresponding to the AF result in the focus detection zone of a plurality of AF frames relevant, can get rid of the outer AF result of this facial subject depth of field, and can select dj as a result than the nearer AF of estimated distance d with this face.The effect aspect, the locational scene that can not be arranged in the pairing health existence of the detected interarea of forecasting institute portion at the health of facial subject is avoided wrong AF.

In the above description, can only select those AF results in the pairing subject depth of field of estimated distance that obtains based on facial size, but also can adopt following structure: the AF result who is adopted as (in the preset range) in the subject depth of field α scope doubly.

Note, in the above description,, then focusing lens are driven into the AF result of facial positions if in the AF of facial positions place success.Yet the result who has a facial positions place is owing to the influence that is subjected to background contrasts causes focusing on too backward possibility.For this reason, can adopt following structure: face to face the portion position and with the AF at the corresponding body position of facial positions place distance near the time, only think that the AF result at facial positions place is correct, and focusing lens moved to the AF result of facial positions.In this case, adopt following structure: if facial positions and keep off with the AF of the corresponding body position of facial positions distance, then the AF result according to body position drives focusing lens.

Note,, then also can for example carry out AF by the focus detection zone being set in picture central authorities if successfully do not detect face.

And, in the above description,, the picture pick-up device with zoom lens and the first-class image pickup optical system of focusing lens has been described, but has been not limited to this as the example of focus adjusting apparatus.For example, can also be focus adjusting apparatus such as telescope and microscope.

Utilize aforesaid structure, even it is low and can not carry out under the situation of AF in facial contrast, perhaps in the focus detection zone, exist to remove under the situation of the different subject of distance facial, also can be to focus on the subject that the user expects with the breakthrough mode of comparing in the past.

In the above description, the signal in the focus detection zone of acquisition imageing sensor calculates the evaluation of estimate of expression focus state, and detects the focusing position of focusing lens, but is not limited to this.For example, the a plurality of focus detection zone of position corresponding to the imageing sensor on the AF sensor that differs among the AF can also be set, focus state in the focus detection zone on the corresponding AF sensor of health of detection and subject, and carry out the mobile control of focusing lens based on focus state.

In the above description, adopted following structure: the position in that the facial pairing health of predicting subject exists is provided with a plurality of focus detection zone, and detects the evaluation of estimate of expression focus state.This point also can be applied to following situation: the evaluation of estimate of the expression focus state that obtains in the single focus detection zone that the position that the facial pairing health of prediction exists is provided with is represented a plurality of focusing positions (referring to Figure 15).In other words, if with the corresponding single focus detection of the body position of subject zone in detect a plurality of focusing positions (among Figure 15 near and far away) of focusing lens, then focusing lens can be moved to the focusing position of focusing lens far away.Like this, even exist in health the place ahead of subject under the situation of the equidistant different subject of vase, desk, also can be to focus on the subject of user's expection with the breakthrough mode of comparing in the past.This is based on the following fact: usually, the health of subject is present on the perpendicular line direction of the facial beginning of subject, and is not free space at this.Even be not this situation, also can be by calculating the subject distance of estimating from facial size and in designated depth, selecting to detect accurately.

Other embodiment

Can reach the purpose of these embodiment by following method.In other words, the storage medium (or recording medium) of the program code of the software that stores the function that is used to realize the foregoing description is provided to system or equipment.The computing machine of this system or equipment (or CPU or MPU) reads and carries out the program code that is stored in this storage medium.In this case, the program code that reads from storage medium is realized the function of the foregoing description, and the storage medium of storing this program code has constituted the present invention.Not only realize the function of the foregoing description, and following situation is also included among the present invention by carrying out the program code that reads by computing machine.In other words, operation operating system (OS) on computers etc. is carried out all or part of actual treatment based on the instruction of this program code, and handles the function that realizes the foregoing description by these.

In addition, following situation is also included among the present invention.Will be from the storer that the program code that storage medium reads is read the function expansion card of insertion computing machine into or the functional expansion unit that is connected with computing machine is set.Also comprise following situation: the CPU that this function expansion card or functional expansion unit are set etc. carries out all or part of actual treatment based on the instruction of this program code, and handles the function that realizes the foregoing description by these.

When applying the present invention to above-mentioned storage medium, will with said process corresponding programs code storage on this storage medium.

Although the present invention has been described, should be appreciated that the present invention is not limited to disclosed exemplary embodiments with reference to exemplary embodiments.The scope of appended claims meets the wideest explanation, to comprise all modifications, equivalent structure and function.

Claims

1. focus adjusting apparatus, it comprises:

The facial positions detecting unit is used to use from the subject image that photographing optical system is caught and carries out the picture signal that the imageing sensor of opto-electronic conversion obtains, and detects in the picture position that people's face at least exists;

The focal point control unit is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture;

Control module is used for controlling the focusing position that obtains the second focus detection zone that focusing position that described focal point control unit obtains with reference to the first focus detection zone that exists at described people's face at least or the health of estimating described people from the position judgment of described people's face exist; And

Judging unit is used for judging in the described first focus detection zone focusing on described people reliability on the face,

Wherein, described control module is based on the judged result of described judging unit, controls focusing position that described focal point control elements reference obtains or with reference to the focusing position that obtains in the described second focus detection zone in the described first focus detection zone.

2. focus adjusting apparatus, it comprises:

The focal point control unit is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture; And

Control module, be used for controlling the focusing position that obtains the second focus detection zone that focusing position that described focal point control unit obtains with reference to the first focus detection zone that exists at described people's face at least or the health of estimating described people from the position judgment of described people's face exist

Wherein, if the difference of the focusing position in focusing position in the described first focus detection zone and the described second focus detection zone is equal to or less than predetermined value, then described control module is controlled the focusing position that described focal point control elements reference obtains in the described first focus detection zone.

3. focus adjusting apparatus, it comprises:

Display unit is used to show the image that obtains from described imageing sensor,

Wherein, if described focal point control unit is by controlling described photographing optical system with reference to the focusing position in described first focus detection zone or the described second focus detection zone, then described focal point control unit focuses on by the detected facial positions of described facial positions detecting unit and shows.

4. focus adjusting method, it may further comprise the steps:

Facial positions detects step, is used to use from the subject image that photographing optical system is caught carry out the picture signal that the imageing sensor of opto-electronic conversion obtains, and detects in the picture position that people's face at least exists;

The focal point control step is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture;

Controlled step, be used to control, so that the focusing position that obtains the second focus detection zone that in described focal point control step, exists with reference to the focusing position that obtains in the first focus detection zone that exists at described people's face or the health of estimating described people from the position judgment of described people's face at least; And

Determining step is used for judging in the described first focus detection zone focusing on described people reliability on the face,

Wherein, described controlled step is controlled based on the judged result of described determining step, so that described focal point control step is with reference to the focusing position that obtains in the described first focus detection zone or with reference to the focusing position that obtains in the described second focus detection zone.

5. focus adjusting method, it may further comprise the steps:

The focal point control step is used for controlling described photographing optical system by the focusing position with reference to the subject image that obtains in the focus detection zone, and wherein said focus detection zone is used to detect the focus state of the described subject image that is positioned at described picture; And

Controlled step, be used to control, so that the focusing position that obtains the second focus detection zone that in described focal point control step, exists with reference to the focusing position that obtains in the first focus detection zone that exists at described people's face or the health of estimating described people from the position judgment of described people's face at least

Wherein, if the difference of the focusing position in focusing position in the described first focus detection zone and the described second focus detection zone is equal to or less than predetermined value, then described controlled step is controlled described focal point control step with reference to the focusing position that obtains in the described first focus detection zone.

6. focus adjusting method, it may further comprise the steps:

Step display is used to show the image that obtains from described imageing sensor,

Wherein, if described focal point control step by controlling described photographing optical system with reference to the focusing position in described first focus detection zone or the described second focus detection zone, then focuses in described focal point control step in described facial positions and detects in the step detected facial positions and show.

7. focus adjusting apparatus, it comprises:

Face-detecting unit is used to use the picture signal of carrying out the imageing sensor acquisition of opto-electronic conversion from the subject image that photographing optical system is caught, and detects the facial position that exists of subject at least;

Focus detecting unit is used at a plurality of focusing positions of estimating to detect with the focus detection zone that is existed by the facial corresponding health of the detected described subject of described face-detecting unit described photographing optical system; And

Control module is used at least one focusing position of obtaining based in described focus detection zone, controls moving of described photographing optical system,

Wherein, described control module is controlled, so as with described photographing optical system move to by in the detected described a plurality of focusing positions of described focus detecting unit with the corresponding focusing position of maximum distance.

8. focus adjusting apparatus according to claim 7, it is characterized in that, described focus detecting unit is provided with a plurality of focus detection zone that prediction is existed by the facial pairing health of the detected subject of described face-detecting unit, and in each zone in described a plurality of focus detection zone, detect the focusing position of described photographing optical system.

9. focus adjusting apparatus according to claim 7 is characterized in that, also comprises:

Estimation unit is used for based on the size by the detected subject face of described face-detecting unit, estimates the subject distance,

Wherein, described control module will in the detected described a plurality of focusing positions of described focus detecting unit not be arbitrary focusing position of the focusing position in the subject depth of field of the described subject distance that described estimation unit obtained, and removes from the focusing position that described photographing optical system moves to.

10. focus adjusting apparatus according to claim 7, it is characterized in that, if with the facial corresponding described focus detection zone, position that exists of the detected described subject of described face-detecting unit in can not detect the focusing position of described photographing optical system, then described focus detecting unit detects the focusing position of described photographing optical system in the described focus detection zone that the facial pairing health of the described subject of prediction exists.

11. focus adjusting apparatus according to claim 7, it is characterized in that, described control module is provided with the indicative control unit that is used to control display part, when controlling described photographing optical system and move to the focusing position of the described photographing optical system in the focus detection zone that the facial pairing health of prediction subject exists with box lunch, the demonstration of focusing at corresponding facial positions place.

12. a focus adjusting apparatus, it comprises:

Face-detecting unit is used to use the subject image by photographing optical system is caught to carry out the picture signal that opto-electronic conversion obtains, and detects the facial information of subject;

Estimation unit is used for from the detected described facial information of described face-detecting unit, estimates the subject distance;

Focus detecting unit is used for detecting the focusing position of described photographing optical system based on described picture signal; And

Control module is used to control so that described photographing optical system is moved to detected focusing position,

Wherein, if detect a plurality of focusing positions, then described control module is based on estimated subject distance, selects the focusing position that will move to described photographing optical system from described a plurality of focusing positions.

13. focus adjusting apparatus according to claim 12, it is characterized in that, described focus detecting unit is based on the picture signal in the focus detection zone, detect the focusing position of described photographing optical system, wherein said focus detection zone is based on the detected facial information of described face-detecting unit.

14. focus adjusting apparatus according to claim 12 is characterized in that, when detecting a plurality of focusing position, described control module is selected the interior focusing position of the subject depth of field of estimated subject distance.

15. focus adjusting apparatus according to claim 12 is characterized in that, when detecting a plurality of focusing position, described control module is selected the focusing position near estimated subject distance.

16. focus adjusting apparatus according to claim 12 is characterized in that, described facial information comprises the information about facial size at least, and described estimation unit is estimated described subject distance based on described facial size information.

17. the control method of a focus adjusting apparatus, it may further comprise the steps:

Face detection step is used to use the subject image by photographing optical system is caught to carry out the picture signal that opto-electronic conversion obtains, and detects the facial position that exists of subject at least;

The focus detection step is used for detecting a plurality of focusing positions of described photographing optical system in estimating the focus detection zone that exists with the facial corresponding health of the detected described subject of described face detection step; And

Controlled step is used at least one focusing position of obtaining based in described focus detection zone, controls moving of described photographing optical system,

Wherein, described controlled step is controlled, so that described photographing optical system is moved in described focus detection step in detected described a plurality of focusing positions and the corresponding focusing position of maximum distance.

18. the control method of a focus adjusting apparatus, it may further comprise the steps:

Face detection step is used to use the subject image by photographing optical system is caught to carry out the picture signal that opto-electronic conversion obtains, and detects the facial information of subject;

Estimating step is used for estimating the subject distance from the detected described facial information of described face detection step;

The focus detection step is used for detecting the focusing position of described photographing optical system based on described picture signal; And

Controlled step is used to control, so that described photographing optical system is moved to detected focusing position,

Wherein, if detect a plurality of focusing positions, then described control module is based on estimated subject distance, selects the focusing position that will move to described shooting optical imagery from described a plurality of focusing positions.

19. a focus adjusting apparatus, it comprises:

Focus detecting unit, be used for first focus detection zone that detected described people's face by described facial positions detecting unit exists and estimate with at least one of the second focus detection zone of the corresponding described people's of detected described people's appearance health existence by described facial positions detecting unit in, detect the focusing position of described photographing optical system; And

Control module is used for controlling moving of described photographing optical system based at least one focusing position from described first focus detection zone and the acquisition of described second focus detection zone,

Wherein, the described second focus detection zone is greater than the described first focus detection zone.